I got my male dog neutered yesterday, and he still has not gone to the bathroom!
He wasn't allowed food/water after midnight the night before but I fed him when he got home which was 24 hours ago! Is this okay?

Sometimes with anesthesia, it can slow an animal down and they may become constipated.

If he hasn't gone by tonight, add some metamucil to his diet. That should help things along.

And I'd call the Vet and ask - out of all the dogs I've owned, all of them neutered, I had one who did have complications.

I always call and ask or at least get a timetable of when this becomes a serious issue.